A066553 - OEIS

A066553

Let N = 1357911131517192123252729313335373941434547495153555759616365676971..., the concatenation of the odd numbers. a(n) is the n-digit number formed from the digits of N starting from the {n(n-1)/2 +1}th digit. Omit any leading zeros.

%I #11 Sep 23 2019 10:07:14

%S 1,35,791,1131,51719,212325,2729313,33537394,143454749,5153555759,

%T 61636567697,173757779818,3858789919395,97991011031051,71091111131151,

%U 1711912112312512,71291311331351371,391411431451471491

%N Let N = 1357911131517192123252729313335373941434547495153555759616365676971..., the concatenation of the odd numbers. a(n) is the n-digit number formed from the digits of N starting from the {n(n-1)/2 +1}th digit. Omit any leading zeros.

%H Harvey P. Dale, <a href="/A066553/b066553.txt">Table of n, a(n) for n = 1..1000</a>

%t With[{nn=20},FromDigits/@TakeList[Flatten[IntegerDigits/@Range[1,(nn (nn+1)), 2]],Range[nn]]] (* Requires Mathematica version 11 or later *) (* _Harvey P. Dale_, Sep 23 2019 *)

%K nonn,base

%O 1,2

%A _Amarnath Murthy_, Dec 17 2001

%E More terms from _Hans Havermann_, Sep 23 2002